Refrigerating apparatus



ay 30, 1933. R E. ROBILLARD. 1,912,333

I iEFRIGERATING APPARATUS Filed Feb. 1951 2 Sheets-Sheet 1 INVENTO v 24. 5'. m4.

M, ms ATTORNEYS.

May 30, 1933.

R. E ROBILLARD REFRI GERATING APPARATUS 2 Sheets-Sheet 2 Filed Feb. 26, 1931 i l I I n r r -INVENTOR 21w. 6'. BY r W Mw-,-( M

7 ms ATTORNEYS.

Patented May 30, 1933 umrsn STAT-ES PATENT OFFICE 3038181 I. 103m, 0! DAYTON, 0810, AS'IGNOB 1'0 rnrcmama CORPORATION, 01' Damn, GHQL CORPORATE! OI' DELLWABE mama-mo arrm'rus Application m Iebrury as, 1m. mm so. 510,450.

The present invention relates to refrigerating apparatus and more particularly.'to reirigerating apparatus of the compression type wherein a lubricant is circulated in a closed cycle with the refrigerant.

Heretofore in refrigerating systems of the compression type trouble has been experienced because oil employed to lubricate operating parts of the system has accumulated on the walls and on top of the liquid refrigerant within the evaporator; This accumulation of oil on the walls and within the evaporator becomes very viscous, as the tem rsture of the evaporator is reduced, and orms a thick layer or blanketon'the refrigerant which hinders or retards eva ration of the liquid refrigerant contained m the evaporator.

The object of the resent invention is to provide means who y the collection of 011 within an eva rator of a refrigerating system' will not inder normal evaporation of refrigerant contained therein.

Another object of the present invention 1s to utilize the one expended by the partial evaporation or the ing of refrigerant enter in an evaporator for agitating the liqu d at a plurality of points within the evaporator to cause circulation of refrigerant therethrough.

Further objects and advantages of the resent invention will be apparent from the Following description, reference being to the accor'npanyin drawings, wherein a preferred form of t e present invention is clearly shown.

In the drawings:

Fig. 1 is a vertical section through a portion of an eva rator having my invention embodied therein and having a refrigerating system shown diagrammatically adapted to be connected with the evaporator;

Fig. 2 is a fragmentary sectional view of a portion of a mechanism contained the eve rater taken on the lines 22 of Fig. 1;

ig. 3 is a fragmentary sectional view of a portion of the evaporator taken on the lines 3-3 ofFig. 1'

Fig. 4 is a view tairen on the lines 44 of Fig. 6 showing a modified form of an evaporator partly in section and partly in elevation embodied therein;

For the purpose ent invention have shown in Fig. 1 a comof illlustrating the pres-v pressor-condenser expander type of refrigeratlng system having an evaporator 10 shown in section on a large scale and including connections 11 and 12 for operatively connecting the evaporator with the system. In addition to theievaporator the system inclhdes a compressor 13, a condenser 14 and a reservoir or liquid refrigerant tank 15. Refrigerant vapor is withdrawn from the evaporator 10 through the vapor or low pressure conduit 16 and is l uefied in the condenser 14 and returned to t evaporator through the liquid or high pressure conduit 17. The compressor is operatai by a motor 18 controlled by an automatic sw tch 19 which may be actuated inresponse tothe refrigerating demand, for example by a pressure-responsive device 21 connected tothe low pressure conduit 16. It is obvious, in systems of the type disclosed, to state that the pressure-responsive device 21 which actuates the switch' 19 for controlling had the electric circuit to the motor is adjusted to operate between certain pressure limitsr' Since pressures and temperatures of the refrigerant increase or decrease uniformly it is apparent that the device 21 is adapted to maintain certain predetermined temperature limits within the evaporator of the system.

Referring to Fig; 1, evaporator 10 comrises a header 24 forming a reservoir for iquid refrigerant, and a plurality of ducts 25 depending from the header 24 for circulating refrigerant to' a intremote from the reservoir. The liqui refrigerant indicated at 26 isliept at a constantlevel 27 by a valve 28 which controls a liquid refrigerant inlet opening 29 extending from the connection 11 through an end plate 30. Valve 28 is actuated in response to the liquid refrigerant level b a float 31. The liquid refrigerant is supp 'ed to the evaporator through the inlet connection 11 and the vapor or gaseous refrigerant is withdrawn through the connection 12 connected to the vapor conduit 16.

The apparatus, or system, as generally described above is lubricated by placing a quantity of oil in the crankcase of the compressor and depending upon the splashing ofthe rotating parts to distribute oil throughout the compressor. Some of the oil is dissolved in the refrigerant and some of the oil is me-- chanically pumped by the compressor to the condenser and reservoir and eventually to the evaporator. The oil in separating by gravity from the refrigerant in the evaporator forms globules which adhere to the walls thereof and tend to remain stationary. These globules of oil form a layer of insulation between the liquid refri erant in the evaporator and the wall thereo which insulation retards the conduction of heat from the evaporator wall to refrigerant contained therein and consequently evaporation of the refri erant is also retarded. Finally after the re rigerantabsorbs suflicient heat to cause its evaporation a disturbance occurs in the evaporator and the globules of oil are carried to the top of the liquid refrigerant. The refrigerant continues to boil off in the evaporator, leaving the oil, which collects in a layer of from to 1 thick on top of the refrigerant.

This collection or accumulation of oil in the evaporator is articularly harmful when the system is used to refrigerate an ice cream cabinet or the like, wherein very low temperatures are desired to be maintained. Under such conditions within the evaporator of the system the compremor will be operated frequently and only for short intervals of time thus causing short operating cycles of the compressor. These short cycles of the compressor are caused by the compressor creating a suction in the low pressure conduit 16 and in the s ace above the liquid level within the he er 24 of the evaporator, suflicient to cause the pressure-responsive device 21 to actuate the automatic switch 19 and break the electric circuit to the motor 18 thus stopping the compressor, withoutbreaking up the layer of oil in the evaporator thereby preventing liquid refrigerant below the layer of oil from vaporizing. Obviously such short cycles of the compressor will continue indefinitely and the evaporator will not be reduced to the temperature at which pressure-responsive device 21 has been set to maintain therein. Consequently the motor which drives the compressor is started an abnormal number of times causi overheatinf thereof. Furthermore, the re igerating e ciency of the evaporator becomes decreased thereby permitting the temperature within the compartment in which the evaporator is located to increase. This inefiicient operation of a system will not maintain substances cooled thereby at the desired temperature and is very likely to permit the substances to deteriorate.

My invention is directed to a system whereby the refrigerant beneath the layer of oil in the evaporator is positively and intermittently agitated at a p urality of points in the evaporator suflicient to cause the blanket or layer of oil to be broken up. This thereby permits liquid refrigerant within the evaporator to vaporize an prevents the compressor from reducing the pressure in the space above the layer of oil and in the low pressure conduit to a degree suficient to eflfec't the pressure-responsive device until the desired low temperature of the evaporator has been obtained. I provide a device which utilizes the energy expended by liquid refrigerant entering the evaporator, of which a portion immediately flashes into vapor as it enters theheader which is maintained at a low pressure, for breaking. up the oil blanket at a plurality of points in the evaporator. Inbreaking up the blanket of oil at a plurality of points in the evaporator m device also more elliciently returns some 0 the oil to the com ressor thus preventing the evaporator rom becoming entirely oillogged. ferring now to Fig. 1' I have provided a means to agitate the liquid within the evaporator at a pluralit of points and this means includes two on ets for incoming liquid refrigerant disposed below the liquid 1e frigerant level in the evaporator. The liquid refrigerant inlet opening 29 leading'to the interior of the header 24 includes a relatively long passage 36 provided in the member 3 to which the arm of float 31 is pivotally mounted.

The valve 28- which controls the inlet opening 29, in response to the movement of the float 31, has a stem rtion 38 extending through the passage A roller 39 secured to the arm of flo'at 31 is adapted to engage the end of thestem portion 38 for moving the valve 28 into en a ment with its seat. It is to be unders that this valve 28 is opened by pressure of the refrigerant in advance of the valve when the float 31 falls and causes the "roller 39 to disengage the stem portion 38 of the valve. Valve stem rtion 38 has two enlargements 41 and 42 ormed thereon which serve to guide the valve 28 in horizontal alignment with its The enlargement 41 is slotted as at 43 (seeTig. 3) topermit the incoming liquid refrigerant to' freely flow past it. A tube or conduit 44 which may be made of a flexible material is soldered or otherwisesecured to an opening in member 37 which opening communicates with the pa 36. This tube extends around the float 31 to a point remote from the inlet 0 ning and near the rear of the. header and me its end disparent that the inner end of the passage 36 and the tube or conduit 44 provides two spaced apart outlets for distributing incoming liquid refrigerant to the reservoir o'r evaporator below the liquid level maintained therein. It is also apparent that the fit of the enlargement 42 within the passage 36 forms a restriction in that passagethereby causing an unequal flow of liquid refrigerant through the outlets for the incoming refrigerant. However, it may be desirable to cause a greater flow of refrigerant through the passage 36 than through the tube or conduit 44 and this may be accomplished by providing slots in the enlargement 42 together with the use of a tube of much smaller diameter in the place of tube 44. The tube 44 being secured as disclosed to the member 37 carried by the end plate 30 can be removed from the evaporator as a unit when the" plate 30 is removed and the elements secured thereto are withdrawn from the header.

In the operation of the system, compressor 13 and condenser 14 liquefies the refrigerant which is then collected in the liquid receiver 15 together with lubricant passing from the compressor. The liquid refrigerant together with the dissolved lubricant are admitted by means of the float actuated valve 28 into the header 24, and, as the refrigerant is evaporated, the gaseous refrigerant is returned through the connection 12 and conduit 16 to the compressor 13. Theoil in header 24 of evaporator 10 floats on top of the liquid re- .frigerant after it has separated from the liquid refrigerant by concentration through the constant evaporation of the refrigerant. The layer of oil on top of the refrigerant in the evaporator becomes more viscous as the temperature of the evaporator is reduced. Since the liquid refrigerant within the evaporator is agitated by the immediate vaporization of a ortion of the incoming refrigerant at a plura ity of points within the evaporator this layer of oil is intermittently broken up and thus permits liquid refrigerant therein to vaporize and be returned to the compressor. An evaporation of refrigerant from the be y of liquid in the reservoir will causethe level therein to fall and consequently the float will drop permitting the inlet valve to open to let more liquid, refrigerant into the reservoir. It is thus apparent that if the greatly increased by the agitation thereof at evaporator is producing an refrigerating effect whatever my improve device willfunction to keep the oil blanket in a state of continuous agitation and thus shortoperating cycles of the compressor ore described are prevented.

In Fig. 4, I have shown a modifiedform of evaporator embodying my invention.

as hereto The construction and arrangjelifient of the evaporator shown in Fig. 4 is y described m a copending applicatlon of Jesse G. King,

Serial No. 236,718, filed November 30, 192

and for this reason it will only be briefly described here. Ducts 51 extend horizontally from the header 24 and communicate with a second header 52. Fins 53 traverse the refrigerant conveying ducts 51 for increasing heat conduction to the refrigerant within the ducts. The header 52 may be spaced any desired distance from the header 24. The

mechanism within the header 24 is identical to the mechanism previously described and shown in the evaporator in Fig. 1, exceptthat the tube 44 is. made much longer so that it will reach into or through one of the ducts 51 to within or near the header 52. By agitating the liquid refrigerant at a plurality of points within anrevaporator of the type disclosed in Fig. 4 an eflicient circulation of refrigerant therein is obtained and the evaporator will have a substantially uniform temperature throughout its length regardless of the distance between the headers 52 and 24. In Fig. 5, I have shown another modified form of evaporator embodying my invention. In this form the header 24 of the evaporator contains the mechanism heretofore described and shown in Fig. 1 and includes a second header or manifold 56 dis sed below the header 24. Ducts 57 extend butwardly and interconnect the header 24 and the manifold 56. In order to agitate the liquid refrigerant within the ducts 57 and within the manifold 56 in addition to within the header24; I provide a duct 58 which also interconnects the header and the manifold. This duct 58 is I secured to the bottom of the header 24 'near the front end thereof and extends at an angle rearwardly and down to the manifold 56. The tube 44 in this modified evaporator structure is also made much longer'than that shown in the evaporator disclosed in Fig. 1 in order to permit the tube 44' to be inserted into the duct 58 when assembling the float valve mechanism into'the header so that it will extend through the duct 58 into or to a point near the manifold 56. It is obvious of course that. the tube 44 in this instance must be made of flexible material to 7 permit such insertion thereof. As before pointed out with respect to the evaporators shown in Figs. 1 and 4, the circulation of refrigerant in all the ducts 57 leading from the manifold 56 in this modification will be a plurality of points within the evaporator and particularly by the agitation of the refrigerant in the manifold 56.

5 very low temperature, which low temperature increases the viscosity of the lubricant, while at the same time providing a means for preventing the lubricant from retarding evaporation of liquid refrigerant in the 1 evaporator. My improved apparatus, by

causing disturbance or agitation of the liquid refrigerant, insures positive and regular circulation of refrigerant through the evaporator. With this accomplished evaporators of the type disclosed are rendered more efiieient for producing very low temperatures. Likewise the life of the compressor and its operating motor is prolonged by the prevention of the heretofore described short operating cycles thereof.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that'other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. .A refrigerating system comprising an evaporator and a, refrigerant liquefying unit operatively connected with the evaporator for circulating a. refrigerant therethrough, said evaporator formin a reservoir for liquid refrigerant and In ricant 1i hter than the liquid refrigerant and ada te to float thereon in a layer, .a duct extending from and communicating with said reservoir for receiving liquid refrigerant therefrom and for delivering liquid refrigerant to a point in said evaporator remote from said reservoir, said evaporator also having a liquid refrigerant inlet opening, a valve for controlling the ingress of refrigerant through said opening, means for actuating said valve, and means for breaking up the layer of lubricant at a plurality of points in the evaporator, said means communicating with said inlet opening for delivering a portion of incoming refrigerant from the opening controlled by the valve to a point below the lubricant level in said evaporator.

2. A refrigerating system comprising an evaporator and a refrigerant liquefying unit operatively connected with the evaporator for circulating a refrigerant therethrough, said eva orator forming a reservoir for liquid re rigerant and lubricant, a duct extending downwardly from and communicating with said reservoir for receivin liquid refrigerant therefrom and for de ivering liquid refrigerant to apoint below said reservoir and remote therefrom, said evaporator also having a liquid refrigerant inlet opening, a valve for controlling the ingress of refrigerant through said opening, means for actuating said valve, and means for agitating the liquid at a plurality of points in the evaporator, said means communicating with said inlet opening for delivering a portion of incoming refrigerant from the opening controlled by the valve to said lower remote point below the liquid level in said evaporator.

3. A refrigerating system comprising an evaporator and a refrigerant liquefying unit operatively connected with the evaporator for circulating a refrigerant therethrough, said evaporator forming a reservoir for li uid refri erant and lubricant, a duct ex ending horizontally from and communicating with said reservoir for receiving liquid refrigerant therefrom and for delivering liquid refrigerant to apoint in said evaporator remote from said reservoir, said evaporator also having a liquid refrigerant inlet opening, a valve for controlling the ingress of refrigerant through said opening, means for actuating said valve, and means for agitating the liquid at a plurality of points in the evaporator, said means communicating with said inlet opening for delivering a portion of incoming refrigerant from the opening controlled by the valve to said remote point below the liquid level in the evaporator.

4. A refrigeratin system comprising an evaporator and a re rigerant liquefying unit operatively connected with the evaporator for circulating a refrigerant therethrough, said evaporator forming a reservoir for liquid refrigerant and lubricant, a duct extending from and communicatin with said reservoir for receivin liquid re rigerant therefrom and for delivering liquid refrigerant to a chamber remote from said reservoir, said evaporator also having a liquid refrigerant inlet opening, means for preventing the rising of liquid within the chamber above a predetermined level, and means for agitating the liquid at a plurality of points in the evaporator, said means communicating with said inlet opening for delivering a portion of incoming refrigerant from said opening to said chamber.

5. A refrigerating system comprising an evaporator and a refrigerant liquefying unit operatively connected with the evaporator for circulating a refrigerant therethrough, said evaporator including an upper and a lower header, ducts interconnecting said headers. said headers together with said ducts formin a reservoir for liquid refrigerant and lubricant, said evaporator having a liquid refrigerant inlet opening, means for preventing the rising of liquid within the evaporator above a predetermined level, means communicating with said inlet openinggmd providing an outlet for delivering a portion of incoming refri erant from said inlet opening to a point wit in said lower header remote from said inlet opening, said outlet being arranged to cause agitation of the liquid in said lower header.

6. A refrigerating system comprising an evaporator and a refrigerant liquefying unit operatively connected with the eva rator for circulating a refrigerant there rough said evaporator forming a reservoir for liquid 5 refrigerant and lubricant, said evaporator also having a liquid refri rant inlet openi disposed below the love of liquid in sai reservoir, a valve for controlling the ingress of liquid refrigerant through said opening, 10 means for actuating said valve to maintam the level of liquid in said reservoir above said inlet opening, and means for conducting the incoming li uid refrigerant from the o nin controlled y the valve to a plum 'ty 0 15 points in the evaporator without permitting said incoming refrigerant to communicate with the free 8 ace above the-liquid in the evaporator, sai last named means communicating with said inlet openin and providin 2o spaced apart outlets disposedlxelow the liqui level in the evaporator.

In testimony whereof I hereto aflix my signature.

ROBERT E. ROBILLARD. 

